Process of liming and dehairing hides



t UNITED sTATEs PATENT oEEIoE.

PETER REMER, F MILWAUKE, WISCONSIN, ASSIG-NOR OF ONE-THIRD T0 ANDREAS G.

\VACKENREUTER AND ONE-THIRD TO WILLIAM S. SHAW, BOTH OF CHICAGO, ILLI- NOIS.

Processes of Liming and Dehairing Hides,

u of which the following is a specification.

l.process This invention relates to a new and improved process of liming and dehairing hides, and it has for its salient objects to put th'e hides in such condition upon the completing ofthe liming and dehairing that they will assimilate the tanning and tan more rapidly and uniformly than heretofore; to put the dehaired hides in such condition that thev will absorb or assimilate more tanning and filler; to plump or swell the hides as a result of the liming and dehairing process with all of the advantages which result from so doing; to provide an inexpensive, rapid and reliable process of liming and dehairing; and .in general, to. provide an improved process of the character referred to. v

My improved process may be carried out by the aid of any suitable series of tanks or receptacles adapted to hold the hides and liquid, and lin the use of which the hides can be transferred from one receptacle to the next in one direction while the treating liquid is transferred from one receptacle to the next progressively in the opposite direction. l

Accordingly I have shown the apparatus in a merely diagrammatic way, since apparatus suitable for carrying out the process is well known to those skilled in the art.

In the drawing the single figure shows a plan view of a series of liming vats connected with each other by 4suitable pipes through which the liquid may flow from one vat to the next.

In the preferred way of carrying out my improved process, I employ a series of nine vats; that number bein accordingly shown in the drawing. The rst and last vats of the series are utilized for preliminary and final washings, respectively, which washings are not strictly parts'of the process.v Accordingly for convenience of description I designate the 'first vat a; number the intermediate vats l to 7, and designate the final Specification of Letters Patent.

PROCESS OF LIMING AND DEHAIRING HIDES.

Patented Feb. 24, 1920.

Application led June 14, 1918. Serial No. 240,009.

washin vat as b the hides being placed in No. 1 a the start, and transferred progressively down the line. The characteristic feature of my process resides in treating; the hides initially in a bath composed of water,

limewater and sulfid of sodium in solution.v

Another important characteristic of -Iny process resides in treating the hides in the final sta s of the process lwith limewater only, an utilizing this same limewater in forming the combined sulid and limewater baths used in the earlier stages of the treatment, whereby the strength of the limewater 1s reduced and lits actlon in combinationwith the sulid improved.

Describing a preferred way of carrying out my process, I first prepare the liquor for the various vats as follows Vats Nos. 7, 6, 5 and 4 are charged with a solution of limewater; vat No.V 7 being charged with the fresh solution about 18 'barkometer strong, vats Nos. 6, 5 and 4 may be initially Charged with solutions which are pro ressively weaker. In the subsequent wor ing -of the process the limewater is transferred from one to the other, and thus becomes weaker in the successive baths.

Vat No. 3 is charged with simple water, which will be changed as often as necessary to insure its operating effectively to wash out the chemical solution remaining in the hides as a result of their previous treatments.

Vats Nos. 2 and 1 are charged with a solul y tion of limewater and suld of sodium. The

lmewater of vat No. 2 is the'same limewater which was used in vat No. 4, from which it is transferred, and to 4this limewater is added from one-half to one pound of sulid of sodium for each hide. The` liquor in vat No.

1 is, in the re ular working of the process,

that which has een transferred from vat No.

2, unmodified except by the change effected by its operation upon the hides. Initially the liquors for vats No. 1 and No. 2 may be vat N o. 2 and therein treated in the same way and for ap roximately the same time as in vat No. 1. ext they are transferred to the washing vat N o. 3 and thoroughly washed inclear water. This washing 1s for the pur ose f eliminatin the sod1um sulfid chargedp liquor as thoroug ly as ract1cable, since there is a tendency to pr uoe a precipitate in and upon the hides 1f the latter are passed into the stronger llme baths before being yproperly washed' free of this solution. The thorough rinsing off of the sulfd solution may be ordinarily accomplished in va short time, say from twenty minutes to a couple of hours.-

From the washing vat No. 3 the h1d es are transferred to vat No. 4, treated thereln for a period of a proximately-twenty-four hours, then trans erred successivelyy to vats Nos. 5, 6 and 7, in each of which they are treated for ap roximately twentyfour hours, and fina ly they are thoroughly Washed out in warm water in vat designated "b. The final washing is, or course, designed to free the hides entirely of the limewater solution to which the have been subjected. It will be noted tiiat in preparing and transferrin the liquors from vat to vat, as suggested, the limewater contained in Vat No. 7 is made as a fresh charge for each batch of hides, and so also the lime and sul-iid solution of vat No. 2 is replenished with the sullid of sodium after the treatment of each batch of hides. Accordingly, after a batch of hides has been taken out of vat No. '1, the liquor of that vat is drained off and the liquor previously contained in vat No. .i2A transferred through the connectin pipe 10, controlled by the turncook 'or v ve 11. The limewater contained in vat No. 4 vis next transferred -to pipe 12 and the requisite amount of suld of sodium added to it. The charges in vats Nos. 5, 6 and 7 are next respectively transferred to the nextlower vat, and a freshly made charge of limewater charged into vat No. 7. T e hides are now treated in the succession of vats as hereinbefore described.

It will, of course, be obvious that the details of treatment may be somewhat variedwithout departing from 'the spirit of my invention, and as well also the solution may be varied.

Hides" which have been subjected toV my improved liming proce are extremely plump, and the lpores thereof expanded and opened up Y so that the hide material is h1 hly absorbent. As a result of this the hides quickly absorb the tanning solution 'to which they are afterward subjected, with vat No. 2` through the.l

the result that the tanning proper is greatly expedited. Moreover, the plum and porous condition of the hides facilitates the absor tion of an increased percentage of so-ca ed filler, with the result of increasing the 'body and Weight of the tanned leather. Hides treated w1th my improved liming process are characterized by an unusual degree .of softness and freedom from harmful effects due to liming.

I claim as my invention:

1. The improved process of liming hides, which consists in first soakin the hides in a hydrous solution, weak in 1me and mild in sodium sulfd, then washing, and thereafter soaking the hides in materially stronger, limewater unmixed with sodium sullid.

2. The improved process of liming hides, which consists in first soaking the hides in a weaker solution of lime and Sodium sulid, thenin a stronger solution of lime and sodium sulfid, then washing the hides free from the sulfid-charged liquor, and thereafter soaking in limewater.

3. The improved process of limin hides, which consists in first soaking the hides in a weaker solution of lime and sodium sulfid, then in a stronger solution of lime and sulfid, then freeing the hides of the sodium.

sulfid, thereafter soaking in a weaker solution of limewater, and then soaking` in a -of moderate strength both as to the sodium sulfid and lime contents, thereafter soakin the hides in a solution of water, lime and sodium sulid stronger than the preceding bath, then washing the hides free of the v sulfi'd-charged liquor, and thereafter sub- Jectln the hides to soaking treatments in a plura ity of baths of limewater, each successively stronger.

5. The improved process ofliming hides,

, whichconsists in passing the hides progressivelg through a Senes of treatment vats in a de nite direction, soaking the hides for a substantial period in each of said treatment vats, concurrently with the transfer of the hldes from vat to vat, transferring the treatment liquor successive] the direction opposite tilI the hides; the hides earller in a solution of water, lime and sulfid of. sodium, treated in the later stages in a solution of lime only, and freed from the sulfid-charged liq^uor between said early stage and later stage treatments.

6. The improved process of liming hides,

at of the progress of which consists in passing the hides progres-.

sively through two series of treatment vats soaking the hides for a substantial period in each treatment vat, the vats of from vat to vat in` 'being treated in thev the first series each containing a solution of to the vats so emptied, whereby the hides lime and sulid of sodium; the vats of the are treated in successively stronger solusecond series containing a solution of lime tions in each series, and Washing the hides 10 only, transferring the treating solutions of in Water between treatments by the first and 5 each series from vat to vat ,of that series second'series.

in the direction opposite that of the progress of the hides and adding fresh solutions PETER REMER. 

